France has said that the international community will need to respond with force if allegations that Syrian government forces had carried out a mass chemical attack on civilians prove to be true.

But the French foreign minister, Laurent Fabius, said there was no question of sending troops on the ground, in an interview with the television network BFM.

He added that if the UN security council could not make a decision, one would have to be taken “in other ways”. He did not elaborate.

Hundreds of people are believed to have been killed in an apparent gas attack on rebel-held parts of eastern Damascus that is thought to be the most significant use of chemical weapons since thousands of Kurds were gassed by Saddam Hussein in Halabja 25 years ago.